usr.bin/indent/indent.1

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.Dd June 28, 2023
.Dt INDENT 1
.Os
.Sh NAME
.Nm indent
.Nd indent and format C program source
.Sh SYNOPSIS
.Nm
.Op Ar input-file Op Ar output-file
.Op Fl bacc | Fl nbacc
.Op Fl bad | Fl nbad
.Op Fl badp | Fl nbadp
.Op Fl bap | Fl nbap
.Op Fl bbb | Fl nbbb
.Op Fl \&bc | Fl nbc
.Op Fl \&bl | Fl \&br
.Op Fl bs | Fl nbs
.Op Fl c Ns Ar n
.Op Fl \&cd Ns Ar n
.Bk -words
.Op Fl cdb | Fl ncdb
.Ek
.Op Fl \&ce | Fl nce
.Op Fl \&ci Ns Ar n
.Op Fl cli Ns Ar n
.Op Fl cs | Fl ncs
.Op Fl d Ns Ar n
.Op Fl \&di Ns Ar n
.Op Fl dj | Fl ndj
.Bk -words
.Op Fl ei | Fl nei
.Op Fl eei | Fl neei
.Ek
.Bk -words
.Op Fl fbs | Fl nfbs
.Op Fl fc1 | Fl nfc1
.Op Fl fcb | Fl nfcb
.Ek
.Op Fl i Ns Ar n
.Op Fl \&ip | Fl nip
.Op Fl l Ns Ar n
.Op Fl \&lc Ns Ar n
.Op Fl \&ldi Ns Ar n
.Op Fl \&lp | Fl nlp
.Op Fl \&lpl | Fl nlpl
.Op Fl npro
.Op Fl P Ns Ar file
.Op Fl pcs | Fl npcs
.Op Fl ps | Fl nps
.Op Fl psl | Fl npsl
.Op Fl \&sc | Fl nsc
.Bk -words
.Op Fl sob | Fl nsob
.Ek
.Op Fl \&st
.Op Fl \&ta
.Op Fl T Ns Ar typename
.Op Fl ts Ns Ar n
.Op Fl U Ns Ar file
.Op Fl ut | Fl nut
.Op Fl v | Fl \&nv
.Op Fl -version
.Sh DESCRIPTION
The
.Nm
utility is a
.Em C
program formatter.
It reformats the
.Em C
program in the
.Ar input-file
according to the switches.
The switches which can be
specified are described below.
They may appear before or after the file
names.
.Pp
.Sy NOTE :
If you only specify an
.Ar input-file ,
the formatting is
done `in-place', that is, the formatted file is written back into
.Ar input-file
and a backup copy of
.Ar input-file
is written in the current directory.
If
.Ar input-file
is named
.Sq Pa /blah/blah/file ,
the backup file is named
.Sq Pa file.BAK
by default.
The extension used for the backup file may be overridden using the
.Ev SIMPLE_BACKUP_SUFFIX
environment variable.
.Pp
If
.Ar output-file
is specified,
.Nm
checks to make sure that it is different from
.Ar input-file .
.Pp
The options listed below control the formatting style imposed by
.Nm .
.Bl -tag -width Op
.It Fl bacc , nbacc
If
.Fl bacc
is specified, a blank line is forced around every conditional
compilation block.
For example, in front of every #ifdef and after every #endif.
Other blank lines surrounding such blocks will be swallowed.
Default:
.Fl nbacc  .
.It Fl bad , nbad
If
.Fl bad
is specified, a blank line is forced after every block of
declarations.
Default:
.Fl nbad .
.It Fl badp , nbadp
This is vaguely similar to
.Fl bad
except that it only applies to the first set of declarations
in a procedure (just after the first `{') and it causes a blank
line to be generated even if there are no declarations.
The default is
.Fl nbadp .
.It Fl bap , nbap
If
.Fl bap
is specified, a blank line is forced after every procedure body.
Default:
.Fl nbap .
.It Fl bbb , nbbb
If
.Fl bbb
is specified, a blank line is forced before every block comment.
Default:
.Fl nbbb .
.It Fl \&bc , nbc
If
.Fl \&bc
is specified, then a newline is forced after each comma in a declaration.
.Fl nbc
turns off this option.
Default:
.Fl \&nbc .
.It Fl \&bl , \&br
Specifying
.Fl \&bl
lines up compound statements like this:
.Bd -literal -offset indent
if (...)
{
  code
}
.Ed
.Pp
Specifying
.Fl \&br
(the default) makes them look like this:
.Bd -literal -offset indent
if (...) {
  code
}
.Ed
.It Fl bs , nbs
Whether a blank should always be inserted after sizeof.
The default is
.Fl nbs .
.It Fl c Ns Ar n
The column in which comments on code start.
The default is 33.
.It Fl cd Ns Ar n
The column in which comments on declarations start.
The default
is for these comments to start in the same column as those on code.
.It Fl cdb , ncdb
Enables (disables) the placement of comment delimiters on blank lines.
With
this option enabled, comments look like this:
.Bd -literal -offset indent
	/*
	 * this is a comment
	 */
.Ed
.Pp
Rather than like this:
.Bd -literal -offset indent
	/* this is a comment */
.Ed
.Pp
This only affects block comments, not comments to the right of
code.
The default is
.Fl cdb .
.It Fl ce , nce
Enables (disables) forcing of `else's to cuddle up to the immediately preceding
`}'.
The default is
.Fl \&ce .
.It Fl \&ci Ns Ar n
Sets the continuation indent to be
.Ar n .
Continuation
lines will be indented that far from the beginning of the first line of the
statement.
Parenthesized expressions have extra indentation added to
indicate the nesting, unless
.Fl \&lp
is in effect
or the continuation indent is exactly half of the main indent.
.Fl \&ci
defaults to the same value as
.Fl i .
.It Fl cli Ns Ar n
Causes case labels to be indented
.Ar n
tab stops to the right of the containing
.Ic switch
statement.
.Fl cli0.5
causes case labels to be indented half a tab stop.
The
default is
.Fl cli0 .
.It Fl cs , ncs
Control whether parenthesized type names in casts are followed by a space or
not.
The default is
.Fl ncs .
.It Fl d Ns Ar n
Controls the placement of comments which are not to the
right of code.
For example,
.Fl \&d\&1
means that such comments are placed one indentation level to the
left of code.
Specifying the default
.Fl \&d\&0
lines up these comments with the code.
See the section on comment
indentation below.
.It Fl \&di Ns Ar n
Specifies the indentation, in character positions,
of global variable names and all struct/union member names
relative to the beginning of their type declaration.
The default is
.Fl di16 .
.It Fl dj , ndj
.Fl \&dj
left justifies declarations.
.Fl ndj
indents declarations the same as code.
The default is
.Fl ndj .
.It Fl \&ei , nei
Enables (disables) special
.Ic else-if
processing.
If it is enabled, an
.Ic if
following an
.Ic else
will have the same indentation as the preceding
.Ic \&if
statement.
The default is
.Fl ei .
.It Fl eei , neei
Enables (disables) extra indentation on continuation lines of
the expression part of
.Ic if
and
.Ic while
statements.
These continuation lines will be indented one extra level.
The default is
.Fl neei .
.It Fl fbs , nfbs
Enables (disables) splitting the function declaration and opening brace
across two lines.
The default is
.Fl fbs .
.It Fl fc1 , nfc1
Enables (disables) the formatting of comments that start in column 1.
Often, comments whose leading `/' is in column 1 have been carefully
hand formatted by the programmer.
In such cases,
.Fl nfc1
should be
used.
The default is
.Fl fc1 .
.It Fl fcb , nfcb
Enables (disables) the formatting of block comments (ones that begin
with `/*\\n').
Often, block comments have been not so carefully hand formatted by the
programmer, but reformatting that would just change the line breaks is not
wanted.
In such cases,
.Fl nfcb
should be used.
Block comments are then handled like box comments.
The default is
.Fl fcb .
.It Fl i Ns Ar n
The number of columns for one indentation level.
The default is 8.
.It Fl \&ip , nip
Enables (disables) the indentation of parameter declarations from the left
margin.
The default is
.Fl \&ip .
.It Fl l Ns Ar n
Maximum length of an output line.
The default is 78.
.It Fl lc Ns Ar n
Maximum length of an output line in a block comment.
The default is 0, which means to limit block comment lines in accordance with
.Fl l .
.It Fl \&ldi Ns Ar n
Specifies the indentation, in character positions,
of local variable names
relative to the beginning of their type declaration.
The default is for local variable names to be indented
by the same amount as global ones.
.It Fl \&lp , nlp
Lines up code surrounded by parentheses in continuation lines.
With
.Fl \&lp ,
if a line
has a left paren which is not closed on that line, then continuation lines
will be lined up to start at the character position just after the left
paren.
For example, here is how a piece of continued code looks with
.Fl nlp
in effect:
.Bd -literal -offset indent
p1 = first_procedure(second_procedure(p2, p3),
\ \ third_procedure(p4, p5));
.Ed
.Pp
With
.Fl lp
in effect (the default) the code looks somewhat clearer:
.Bd -literal -offset indent
p1\ =\ first_procedure(second_procedure(p2,\ p3),
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ third_procedure(p4,\ p5));
.Ed
.Pp
Inserting two more newlines we get:
.Bd -literal -offset indent
p1\ =\ first_procedure(second_procedure(p2,
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ p3),
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ third_procedure(p4,
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ p5));
.Ed
.It Fl \&lpl , nlpl
With
.Fl \&lpl ,
code surrounded by parentheses in continuation lines is lined up even if it
would extend past the right margin.
With
.Fl \&nlpl
(the default), such a line that would extend past the right margin is moved
left to keep it within the margin, if that does not require placing it to
the left of the prevailing indentation level.
These switches have no effect if
.Fl nlp
is selected.
.It Fl npro
Causes the profile files,
.Sq Pa ./.indent.pro
and
.Sq Pa ~/.indent.pro ,
to be ignored.
.It Fl P Ns Ar file
Read profile from
.Ar file .
.It Fl pcs , npcs
If true
.Pq Fl pcs
all procedure calls will have a space inserted between
the name and the `('.
The default is
.Fl npcs .
.It Fl ps , nps
If true
.Pq Fl ps
the pointer dereference operator (`->') is treated like any other
binary operator.
The default is
.Fl nps .
.It Fl psl , npsl
If true
.Pq Fl psl
the names of procedures being defined are placed in
column 1 \- their types, if any, will be left on the previous lines.
The
default is
.Fl psl .
.It Fl \&sc , nsc
Enables (disables) the placement of asterisks (`*'s) at the left edge of all
comments.
The default is
.Fl sc .
.It Fl sob , nsob
If
.Fl sob
is specified, indent will swallow optional blank lines.
You can use this to
get rid of blank lines after declarations.
Default:
.Fl nsob .
.It Fl \&st
Causes
.Nm
to take its input from stdin and put its output to stdout.
.It Fl ta
Automatically add all identifiers ending in "_t" to the list
of type keywords.
.It Fl T Ns Ar typename
Adds
.Ar typename
to the list of type keywords.
Names accumulate:
.Fl T
can be specified more than once.
You need to specify all the typenames that
appear in your program that are defined by
.Ic typedef
\- nothing will be
harmed if you miss a few, but the program will not be formatted as nicely as
it should.
This sounds like a painful thing to have to do, but it is really
a symptom of a problem in C:
.Ic typedef
causes a syntactic change in the
language and
.Nm
cannot find all
instances of
.Ic typedef .
.It Fl ts Ns Ar n
Assumed distance between tab stops.
The default is 8.
.It Fl U Ns Ar file
Adds type names from
.Ar file
to the list of type keywords.
.It Fl ut , nut
Enables (disables) the use of tab characters in the output.
The default is
.Fl ut .
.It Fl v , \&nv
.Fl v
turns on `verbose' mode;
.Fl \&nv
turns it off.
When in verbose mode,
.Nm
reports when it splits one line of input into two or more lines of output,
and gives some size statistics at completion.
The default is
.Fl \&nv .
.It Fl -version
Causes
.Nm
to print its version number and exit.
.El
.Pp
You may set up your own `profile' of defaults to
.Nm
by creating a file called
.Pa .indent.pro
in your login directory and/or the current directory and including
whatever switches you like.
A `.indent.pro' in the current directory takes
precedence over the one in your login directory.
If
.Nm
is run and a profile file exists, then it is read to set up the program's
defaults.
Switches on the command line, though, always override profile
switches.
The switches should be separated by spaces, tabs or newlines.
.Pp
.Ss Comments
.Sq Em Box
.Em comments .
The
.Nm
utility
assumes that any comment with a dash or star immediately after the start of
comment (that is, `/*\-' or `/**') is a comment surrounded by a box of stars.
Each line of such a comment is left unchanged, except that its indentation
may be adjusted to account for the change in indentation of the first line
of the comment.
.Pp
.Em Straight text .
All other comments are treated as straight text.
The
.Nm
utility fits as many words (separated by blanks, tabs, or newlines) on a
line as possible.
Blank lines break paragraphs.
.Ss Comment indentation
If a comment is on a line with code it is started in the `comment column',
which is set by the
.Fl c Ns Ns Ar n
command line parameter.
Otherwise, the comment is started at
.Ar n
indentation levels less than where code is currently being placed, where
.Ar n
is specified by the
.Fl d Ns Ns Ar n
command line parameter.
If the code on a line extends past the comment
column, the comment starts further to the right, and the right margin may be
automatically extended in extreme cases.
.Ss Preprocessor lines
In general,
.Nm
leaves preprocessor lines alone.
The only
reformatting that it will do is to straighten up trailing comments.
It
leaves embedded comments alone.
Conditional compilation
.Pq Ic #ifdef...#endif
is recognized and
.Nm
attempts to correctly
compensate for the syntactic peculiarities introduced.
.Ss C syntax
The
.Nm
utility understands a substantial amount about the syntax of C, but it
has a `forgiving' parser.
It attempts to cope with the usual sorts of
incomplete and malformed syntax.
In particular, the use of macros like:
.Pp
.Dl #define forever for(;;)
.Pp
is handled properly.
.Sh ENVIRONMENT
The
.Nm
utility uses the
.Ev HOME
environment variable.
.Sh FILES
.Bl -tag -width "./.indent.pro" -compact
.It Pa ./.indent.pro
profile file
.It Pa ~/.indent.pro
profile file
.El
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .
.Sh BUGS
The
.Nm
utility has even more switches than
.Xr ls 1 .
.Pp
A common mistake is to try to indent all the
.Em C
programs in a directory by typing:
.Pp
.Dl indent *.c
.Pp
This is probably a bug, not a feature.